Re: [PATCH 3/3] serial: 8250: Add a wakeup_capable module param

From: Paul E. McKenney
Date: Tue Jan 17 2012 - 23:17:48 EST


On Tue, Jan 17, 2012 at 08:10:36PM +0000, Alan Cox wrote:
> On Tue, 17 Jan 2012 10:56:03 -0800
> Simon Glass <sjg@xxxxxxxxxxxx> wrote:
>
> > Since serial_core now does not make serial ports wake-up capable by
> > default, add a parameter to support this feature in the 8250 UART.
> > This is the only UART where I think this feature is useful.
>
> NAK
>
> Things should just work for users. Magic parameters is not an
> improvement. If its a performance problem someone needs to fix the rcu
> sync overhead or stop using rcu on that path.

I must say that I lack context here, even after looking at the patch,
but the synchronize_rcu_expedited() primitives can be used if the latency
of synchronize_rcu() is too large.

Thanx, Paul

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